A vane-type negative pressure pump that generates negative pressure due to power from an engine is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2004-285978. In this negative pressure pump, a rotor that supports a vane is passed-through the bottom portion of a housing that is shaped as a cylinder having a bottom, and the outer peripheral surface of this rotor contacts a portion of the inner wall surface of the housing. Further, in the bottom portion of the housing, an intake port is formed, and a discharging port is formed at the vane rotating direction downstream side of this intake port, respectively. Further, a notch that, at the time when the vane that has gone past the discharging port compresses the space between the rotor, becomes a relief passage for releasing gas and lubricant from the compressed space to a space (a space including the intake port) where the pressure is lower than the compressed space, is formed in the outer peripheral surface of the rotor. Excessive pressure (force that attempts to push the vane back) being applied to the vane is suppressed by this notch.